The present invention relates to an oil guiding housing and, more particularly, to a housing which is detachably fastened to a flange of the crankcase and ensures a targeted guiding of all lubricating oil flows and provides a good degassing of the lubricating oil of an internal-combustion engine.
The supply of an internal-combustion engine installed in a motor vehicle with lubricating oil under all operating conditions is a known problem. Critical conditions may occur, for example, when driving in steep terrain or, as a result of high centrifugal forces, during fast cornering. Under such conditions, the oil collects in the internal-combustion engine in areas from which no sufficient recirculating can take place into the lubricating system. Particularly in the case of high-speed internal-combustion engines, an air roll caused by the crankshaft drive and rotation in the crankcase hinders the return flow of the oil flowing out of the cylinder heads and causes an undesirable foaming.
In order to eliminate these problems, it is known, as shown DE-OS 27 51 982, to provide a return flow duct for the lubricating oil flowing back out of the cylinder heads which is cast into the end of the crankcase. From this duct, the oil reaches a closed duct which is arranged on the bottom of the flat oil pan part and leads into the oil sump.
In German Patent 36 24 325 C1, an oil pan is provided a sunk recess for the oil sump. The recess is partially covered by a metal sheet. The oil flowing back into the sump, by way of the metal sheet, is guided to a recess wall situated in the air stream whereby the oil is to be sufficiently cooled. This type of an arrangement cannot be used if the recess is covered by other components on the internal-combustion engine or the underbody of the motor vehicle is covered in order to achieve improved aerodynamics.
It is also known, particularly in motor sports, to provide a dry-sump lubrication. In this situation, in addition to the pump taking in oil from the crankcase, an additional pump is required which takes in the oil from a storage tank and supplies it to the internal-combustion engine under pressure. This solution requires two pumps and a corresponding number of lines with couplings and therefore requires high constructive expenditures and is expensive. In addition, the second pump produces loud noises, particularly in the case of high rotational speeds. The advantage is the fast recirculation of the oil into the lubricating system, a good degassing as well as a lubricating oil supply which is ensured also under extreme conditions.
It is an object of the present invention to avoid the above-mentioned disadvantages, particularly those of a dry-sump lubrication system and to ensure in an internal-combustion engine a targeted guiding of the lubricating-oil flows, an improved defoaming of the oil and an optimum supply of the internal-combustion engine with lubricating oil under all operating conditions.
This object has been achieved in accordance with the present invention by providing an oil guiding housing which has a pan part bounding the crank space in the downward direction and extending essentially parallel with respect to the crankshaft. Return flow devices which are separated from one another as well as a forward flow device are integrated in the housing for the lubricating oil. At one end of the oil guiding housing, a storage tank is arranged below the pan part into which the lubricating oil collected in the return flow devices flows by way of a single inlet opening. Inside the storage tank, a delay part and an oil pum are arranged to deliver the lubricating oil via the integrated forward flow device to the other end of the oil guiding housing. There, below the pan part on a housing part, a flange surface is arranged for the fastening of an oil filter. In the housing part, a thermostat is arranged for the oil-temperature-dependent control of the lubricating oil flow either by way of an oil cooler or directly into the internal-combustion engine.
The oil guiding housing of the present invention has the advantages of a dry-sump lubrication while avoiding its disadvantages. The separate lines and couplings which are required in the case of a dry-sump lubrication because of the physical separation of the oil pan and the storage tank are unnecessary because all required oil-carrying lines are integrated in the present invention. The configuration of the pan part, together with the part of the crankcase arranged above it, ensures a complete separation of the foamed oil flowing back from the crankshaft drive and the part of the lubricating oil which flows from the remaining points of the internal-combustion engine into the storage tank. In this storage tank, as a result of the delay part, the immediate short-circuit-type intake of the foamed oil by the oil pump is avoided and the oil is largely degassed.
The inlet opening, by virtue of which the pan part and the storage tank are connected with one another, is arranged almost centrally with respect to a horizontal cross-sectional plane of the storage tank. Thus, even in the case of extreme displacements of the oil level in the storage tank, a flowing-back into the pan part is prevented. In this situation, the delay part additionally avoids an excessively fast flowing-off of the oil from the direct environment of the intake strainer of the oil pump.
The arrangement of the oil filter on a housing part situated below the pan part prevents an emptying of the filter after the internal-combustion engine is switched off and thus an intake of air which, when the engine is restarted, may reach the lubricating system. Adjacent to the oil filter, the thermostat is integrated in this housing part which connects and disconnects the oil cooler.
A wall, which is arranged at one end of the oil guiding housing and which simultaneously bounds the pan part and the storage tank, is used as a large-area flange for a transmission so that a rigid connection is ensured of the internal-combustion engine and the transmission.
Preventing the oil which is not used for the immediate lubricating of the crankshaft drive from reaching the crankshaft drive as well as the above-described thorough degassing of the oil together have the effect that the components which require clean oil, such as the slide bearings, the hydraulic valve play compensating elements and the hydraulically actuated mechanisms for variable valve controls, can be operated without any problems at high rotational speed ranges.
At its underside situated opposite the inlet opening, the storage tank is closed off by a pan-shaped covering which makes the oil pump accessible. The delay part is constructed to be flange-shaped at its edge and has sealing devices that are integrated there. This edge is braced in the parting line between the storage tank and the covering and thus prevents an outflowing of oil. Adjacent to the edge, several passages are arranged which form the only connection from the storage tank to the strainer of the oil pump situated below the delay part.
The top side of the pan part, as part of the return flow device, has first and second grooves of which the first one is closed off by a corresponding design of a wall of the crankcase disposed above it. By way of several return flow ducts arranged along the internal-combustion engine, the oil flowing back from the cylinder heads is guided into this groove. A flowing of the oil out of the heads is therefore ensured even if the internal-combustion engine is tilting excessively. The covering of the second groove takes place by a rib arranged in the crankcase. The rib is placed in the direction of the crankshaft and has the effect of an oil lathe. The oil thrown off by centrifugal force, by way of the rib, arrives in this second groove which also receives oil flowing back from the cylinder heads.
The entire oil guiding housing, comprising the pan part, the housing part and the storage container, may be manufactured in one piece as a metallic diecast part or be made of plastic or be constructed from separate components. A one-piece construction as an aluminum diecast part ensures an inexpensive and fast manufacturing with precise measurements because no undercuts occur as a result of a corresponding design.